We are observing the same behavior today.
> On 24 Feb 2026, at 19:10, Jarland Donnell via mailop <[email protected]> > wrote: > > Now that you mention it, some emails do seem to just not be getting through. > In the last 17 hours we've successfully delivered 46549 emails to Microsoft, > and we've given up on 3256. And I've noticed new language via support: > > "The connection and throttling limitation against your IP > > 136.175.108.47 > 136.175.108.64 > 136.175.108.0 > 136.175.108.29 > 136.175.108.89 > 136.175.108.130 > 136.175.108.148 > 136.175.108.84 > > has been set to a more appropriate level based on your reputation." > > I'm debating adding a /24 to our outbound to see if that clears up the last > stretch, as it seems that either this is a new throttling system or they're > leaning more heavily on an older one than they were just 48 hours ago. If I > go through with it, I'll keep you guys posted on whether or not it clears > things up. > > On 2026-02-24 10:13, Paul Smith* via mailop wrote: >> On 24/02/2026 12:45, Gellner, Oliver via mailop wrote: >>> We receive the same error messages for all servers since 2026-02-23 18:45 >>> UTC. It's unlikely that Microsoft suddenly received spam from all IP >>> addresses of all kind of unrelated organizations yesterday evening. >>> Probably some algorithm went nuts there. >> I thought we were being *rate limited*, but we're not, nothing at all is >> going out to outlook.com <http://outlook.com/>, hotmail.com >> <http://hotmail.com/>, etc. Mail to business M365 is going out fine. >> The last one we sent successfully was at 16:42 UTC yesterday >> hotmail-com.olc.protection.outlook.com >> <http://hotmail-com.olc.protection.outlook.com/> | 2026-02-23 >> 18:42:59.270101+00 >> eur.olc.protection.outlook.com <http://eur.olc.protection.outlook.com/> >> | 2026-02-23 18:15:08.699069+00 >> hotmail-com.olc.protection.outlook.com >> <http://hotmail-com.olc.protection.outlook.com/> | 2026-02-23 >> 18:00:08.615426+00 >> hotmail-com.olc.protection.outlook.com >> <http://hotmail-com.olc.protection.outlook.com/> | 2026-02-23 >> 17:59:20.363448+00 >> eur.olc.protection.outlook.com <http://eur.olc.protection.outlook.com/> >> | 2026-02-23 17:45:34.862099+00 >> hotmail-com.olc.protection.outlook.com >> <http://hotmail-com.olc.protection.outlook.com/> | 2026-02-23 >> 17:45:09.072445+00 >> outlook-com.olc.protection.outlook.com >> <http://outlook-com.olc.protection.outlook.com/> | 2026-02-23 >> 17:45:05.513997+00 >> eur.olc.protection.outlook.com <http://eur.olc.protection.outlook.com/> >> | 2026-02-23 17:39:01.241583+00 >> outlook-com.olc.protection.outlook.com >> <http://outlook-com.olc.protection.outlook.com/> | 2026-02-23 >> 17:37:07.033491+00 >> hotmail-com.olc.protection.outlook.com >> <http://hotmail-com.olc.protection.outlook.com/> | 2026-02-23 >> 17:30:14.199864+00 >> eur.olc.protection.outlook.com <http://eur.olc.protection.outlook.com/> >> | 2026-02-23 17:30:09.456287+00 >> I've sent support messages to Microsoft (via https://olcsupport.office.com/ >> ), but we get an automated response saying 'there's no reason you can't send >> mail to Outlook.com <http://outlook.com/>'. I've sent a follow up email >> message to hopefully get a human response, but no replies at all yet >> Paul >> _______________________________________________ >> mailop mailing list >> [email protected] <mailto:[email protected]> >> https://list.mailop.org/listinfo/mailop > _______________________________________________ > mailop mailing list > [email protected] <mailto:[email protected]> > https://list.mailop.org/listinfo/mailop
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